Phase Control Of Resonance-fluorescence Of A Driven Cascade Three-level Atom

Spontaneous emission is one of the most severe limiting factors for the storage and propagation of quantum information, high frequency laser, high precision measurement, and many other novel discoveries in modern quantum optics. For the study for controlling spontaneous emission is one of the important forward subjects in laser physics and quantum optics. The basic mechanisms for controlling spontaneous emission in the free space are quantum coherence and interference, which have led to a great number of novel effects such as electromagnetically induced transparency, las-ing without inversion, subluminal and superluminal light propagation and enhanced nonlinear processes in the ultraslow propagation regimes, and so on. These novel effects have many potential applications in quantum optics and nonlinear optics.In this paper we study spontaneous emission of a three-level cascade atom driven by a pair of bichromatic fields of equal frequency differences. These characteristic features are found. The fluorescence spectra depend crucially on the difference between the relative phase of the two bichromatic fields, φ =φ₁ — φ₂) — (φ₃ — φ₄), where φ_i(i = 1 - 4) are the phases of the pair of bichromatic fields. The fluorescence spectra are eliminated selectively as the relative phase difference is varied. At the same time, when the conditions are satisfied: , Ω_i and γ_j(i = 1 — 4, j = 1,2) are the complex Rabi frequencies of the two bichromatic fields and atomic rates of decay from |2 〉to |1〉 and from |1〉 to |0〉, respectively, and when â–³₁ =â–³₂ = 0(â–³₁ = ω_a — ω₂₁, â–³₂ = ω₁₀ — ω_b), all spectral peaks are suppressed as the phase difference φ is varied. when 0 = 0, the spectral peaks vanish. Finally, these features have been analyzed in the terms of dressed states produced by the driving fields. In fact, the phase dependence of fluorescence spectra is attributed to the fact that four different field components induce the transitions in a closed loop configuration. And under , and â–³₁ = â–³₂ = 0 conditions, the one-photon absorption and the two-photon absorption are greatly suppressed since destructive interference.